Machine for trimming the finger plate on a piano key



mm 13, 1956 H. D. OSLUND 77@26;8

MACHINE FOR TRIMMING THE FINGER PLATE ON A PIANO KEY Filed May 5, 1955 2' Sheets-Sheet 1 FIG! . INVENTOR. HERBERT D. OSLUND ATTORNEY H. D. OSLUND Wmr. 3, 1956 MACHINE FOR TRIMMING THE FINGER PLATE ON A PIANO KEY 2 Sheets-Sheet 2 Filed May 5, 1955 .INVENTDR. HERBERT D. OSLUIND FIQB l ll/l/l/V /I/ Ill llll W n f m m m M United States Patent MACHINE FOR TRINIMING THE FINGER PLATE ON A PIANO KEY Herbert D. Oslund, Minneapolis, Minn.

Application March 5, 1953, Serial No. 340,604

6 Claims. (Cl. 144-2) My present invention relates to a machine for trimming the finger plate on a piano key and is in the nature of an improvement or refinement of a similar machine disclosed and broadly claimed in my Uni-ted States Letters Patent No. 2,544,175, issued March 6, 1951.

An object of this invention is to mount an electric motor on the machine with a direct drive to the cutters.

Another object is to provide a novel guard for one of the cutters.

Still another object is to provide novel means for assembling the machine and for securing certain parts thereto.

These and other objects will be apparent from the following description, reference being had to the drawings.

To the above end, the invention consists of the novel construction, arrangement, devices and combination of devices hereinafter described and defined in the claims.

in the accompanying drawings, which illustrate the invention, like characters indicate like parts throughout the several views.

Referring to the drawings:

Fig. 1 is a plan view of the machine, with some parts broken away;

Fig. 2 is a front eleva-tional view of the same;

Fig. 3 is a view partly in elevation and partly in longitudinal central section taken on the line 3-3 of Fig. 1;

Figs. 4 and 5 are fragmentary views partly in end elevation and partly in transverse vertical section taken on the lines 4-4 and 55 of Fig. 3, respectively;

Fig. 6 is a fragmentary view partly in front elevation and partly in longitudinal section taken on the line 6-6 of Fig. 7;

Fig. 7 is a view partly in end elevation and partly in transverse vertical section taken on the line 7-7 of Fig. 3 with the spacer in an open position;

Fig. 8 is a bottom plan view of the table and a fragment of the base to which it is hinged;

Fig. 9 is a detail view principally in transverse vertical section taken on the line 99 of Fig. 3;

Fig. 10 is a detail view principally in horizontal section taken on the line 10- 10 of Fig. 9;

Fig. 11 is a fragmentary detail view of one of the hinge pins and associated parts, on an enlarged scale; and

Fig. 12 is a fragmentary detail view principally in elevation with some parts sectioned on the line 1;212 of Fig. 7 and with some parts removed.

The numeral .13 indicates a rectangular main base having relatively high side and end walls 14. Integral with the right-hand end wall 14 is a rectangular motor base 15 that is relatively low.

An electric motor 16, fragmentarily shown, is mounted on the motor base 15 with its armature shaft 17 extending longitudinally over said base in axial alignment with an arbor 1 8 journaled in a pair of axially aligned bushings 19 turnable in a pair of laterally spaced bearings 19, each detachably secured .to a base 20 by a screw 20' having its head countersunk in the bottom of said base. Fig. 5. The bearing base 20 is detachably secured to the main base 13 by screws 21 and the bearings 19 are each turnably 2,770,268 Patented Nov. 13, 1956 ice secured to the base 20 by a screw 21, as shown in Fig. 4. Formed in each bushing 19 is a longitudinal slot 19" that extends the full length thereof, for a purpose which will presently appear. The purpose of detachably securing the bearings 19 to their base 19 is to permit realignment of their bushings 19', for repair and for adjustment. A universal joint 22 having a pliable intermediate section 23 of rubber or other suitable material connects the armature shaft 17 to the arbor 18.

The two bearings 19 are connected and positively held from turning relative to their base 20 and each other by a horizontal thin flat plate 24 that extends radially outwardly from the axis of the arbor 18. This plate 24 at its end portions is mounted in slots 25 in the bearings 19 with its inner longitudinal edge portion extending into the slot 19" in the bushings 19. A pair of binding screws 26 having threaded engagement one with each bearing 19impinge the plate 24 and frictionally clamp said plate onto the bearings 19. Obviously, the plate 24 holds the bearings 19 from turning on the base 20 and from turning movement in respect to each other. The plate 24 also acts as a shim and as the bushings 19 and the arbor 18 wear a plate may be substituted for the original plate.

A relatively large circular cutter 27, having thick teeth, is secured on the arbor 18 outwardly of the righthand bear ing 19. A circular cutter 2.; having thin teeth is secured to the arbor 18 outwardly of the lefthaud bearing 19. The cutter 27 worlos in a thin housing 29 that affords a guard for said cutter. This housing 29 has on its front a base flange 30 that rests on the base 13 and is secured thereto by machine screws 31. In the front of the housing 29 is a deep notch 32 in which the hub 33 of the cutter 27 works and the back of said housing is open. The sides of the lower half of the housing 29 are perpendicular to the base 13 and the upper half of said housing is substantially concentric to the cutter 27. The top portion of the cutter 27 between the sides of the notch 32 is exposed for work.

An elongated rectangular table 34 overlies the bearings 19 and the cutter 28 and its right-hand end is close to the housing 29. Integral with the front and rear longitudinal edges of the table 34 and also with the left-hand edge of said table is a narrow apron 35. Integral with the rear section of the apron 35 is a wide rearwardly and downwardly inclined web 36.

The rear longitudinal edge portion of the web 36 is enlarged to afford a round hinge member 37 that extends the full length of said web between a pair of bearings 38 integral with the base 13. A pair of hinge pins 39, in the form of screws, have threaded engagement with the bearings 33. These hinge pins 39 have conical inner ends 40 that extend into correspondingly formed seats 41 in the end portions of the hinge member 37. Lock nuts 39 on the hinge pins 39 prevent accidental turning thereof. Figs. 1, 5 and 11. Obviously, the web 36 in addition to supporting the table 34 also affords a guard for the cutter 28.

Normally, the table 34 is yieldingly held raised by a coiled spring 42 expanded to its full length and encircling a pin 43. This pin 43 has threaded engagement, at its lower end portion, with the bearing base 29 and held by a lock nut 44 from turning. The pin 43 above the spring 42 extends loosely through a hole 45 in the web 36.

A depending sheet metal guard 46 extends along the front longitudinal section of the apron 35 and also along the left-hand section of said apron. The guard 46 has on its upper longitudinal edge an inturned flange 4-7 secured to the apron 35 by screws 48. The guard 46, at the front of the table 34, has at its lower longitudinal portion an extension 46' that extends horizontally outwardly over the base 13 and downwardly outwardly of said base and .caps the same when the table 34 is depressed, Fig. 5.

When the table 34 is depressed against the tension of the spring 42 into a horizontal position, the guard 46 extends nearly to the base 13. An adjustable stop 48 limits the depression of the table 34 and is in the form of a long upright bolt having screw-threaded engagement with the bearing base 20 forward of the bearings 19. As the table 34 is depressed, the front section of the apron 35, exposed through an aperture 50 in the flanges 47 (Fig. strikes the head 51 of the bolt 49 and stops said table. A lock nut 49 on the bolt 49 prevents the bolt 49 from being accidentally turned. Figs. 3 and 8.

Resting on the table 34, at its transverse center, are two supporting blocks 52 and 53 spaced endwise apart longitudinally of the table 34. Formed in the blocks 52 and 53 at their transverse centers is a channel 54 that extends completely longitudinally through said blocks. A long slot 55 is formed in the table 34 and the longitudinal axis of the arbor 18, the channel 54 and the slot 55 are all in the same vertical plane.

Each block 5253 is detachably secured to the table 34 by a machine screw 56 that extends from under/the table 34 upwardly through an enlargement in the width of the slot 55, has threaded engagement with the respective block 52--53 and its head impinges the under side of the table 34. Figs. 3 and 8. Both blocks 52 and 53 at their tops are inset at 52' to form at the outer end portions of said blocks a work-supporting ridge 53'. The ridges 53 extend transversely the full width of the blocks 52 and 53 and their tops are flat in the same horizontal plane. Figs. 1 and 2. The purpose of the ridges 53' is to provide two-point contact for a piece of work resting thereon and to prevent the same from rocking while being fed to the cutter 27.

A long flat work guide plate 57 extends endwise longitudinally through the channel 54 at its transverse center and is perpendicular to the table 34. The right-hand end of the guide plate 57 extends materially outwardly of the cutter 27 on its left-hand end and is substantially at the center of the block 53.

Formed in the lower longitudinal edge portion of the guide plate 57 is a deep notch 58 in which the cutter 27 works. The guide plate 57 is rigidly secured to the block 52 by forming in its lower longitudinal edge portion, at the longitudinal center of the block 52 a wide notch 59 zto provide a pair of legs 60 that extend through slots 61 in the ends of the block 52 at the bottom of the channel 54, with a pressed fit. The guide plate 57, at the bottom of the notch 59 straddles and rests on the block 52 at the bottom of the channel 54 and the legs 60 at their lower ends, extend into the slot 55 with a close transverse fit. Formed with the block 53 is a pair of short legs 62 that extend into the slot 55 in the table 34 with a close transverse fit. The guide plate 57 within the block 53 is spaced above the bottom of the channel 54 and is entirely independent of said block.

The cutter 27 works in a slot 13 in the base 13 and the cutter'27, when the table 34 is depressed, works in a slot 63 in said table. Figs. 3, 4, 7 and 8.

Mounted on the outer end portion of the guide plate 57 is an adjustable stop block 64 having in its under side a deep groove 57 through which said guide plate extends with a working fit. That portion of the guide plate 57 on which the stop block 64 slidably rests is reduced in width to lower said stop block into a predetermined relation to the cutter 27. In the end of the stop block 64 facing the cutter 27 is a wide intermediate recess 65 that extends completely through said block from the top to bottom.

To lock the stop block 64 to the guide plate 57 in different adjustments relative to the cutter 27, I provide a bolt 66 having a square head 67 and a wing nut 68. The bolt 66 extends upwardly through a bore 69 in the stop block 64 parallel to the guide plate 57. The bore 69 at its lower end portion is enlarged in diameter to receive the bolt head 67 and expose the adjacent side of the guide plate 57. The wing nut 68 rests on the top of the stop block 64 and holds the bolt 66 suspended in the bore 69 with its head 67 in engagement with the stop block 64 at the upper end of the enlarged portion of the bore 69 as a base of resistance. The bolt head 67 is free for a slight turning movement in the bore 69 whereby, when the wing nut 68 is tightened on the bolt 66, its head 67 at one of its corners will be turned into contact with the guide plate 57 and thereby lock the stop block 64 to said guide plate.

Each of the two corners of the outer end of the block 53 is notched to provide two flat parallel stop shoulders 70 and 71 that are perpendicular to the plane of the cutter 28. The block 53 between the stop shoulders 70--71 overlies the cutter 28 and is spaced above the table 34 to leave a work passageway 72 to the cutter 28. The under side of the block 53, between the stop shoulders 70-71, is on the arc of a circle having its center at the axis of the cutter 28 to provide working clearance for the cutter 27.

I provide a spacer 73, in the form of an upright horizontally elongated flat plate having on its back an integral long hinge member 74 that extends into a horizontal slot 75 in the block 53, and is attached thereto by a hinge pin '76. When the spacer 73 is closed, it is flatwise against the outer end of the block 53. Figs. 1, 2 and 3.

The perimeter of the cutter 28 and its teeth are wiped with an oil saturated swab 77 to reduce friction while cutting a piece of work. As shown, the swab 77 is a piece of felt held by a clip 78 for-med by the free upper end portion of a flat spring arm 79. This arm 79 at its lower end portion is bent outwardly parallel to the table 34 and secured thereto by a screw 80. The arm 79 is upwardly inclined toward the cutter 2'8 and yieldingly presses the swalb 77 against the respective side of said cutter and its teeth to keep the same oiled. Figs. 3, 6 and 1:2.

The operation of the device to turn a blank key to the proper form may be briefly described as follows.

The stop block 64 must be adjusted to determine the transverse cuts to be made in the longitudinal edge portions at the rear end of the wide front end portion of the key. One of these cuts is relatively shallow and the other relatively deep. These two cuts determine the width of the narrow or rear end portion of the keys. The stop 49 is adjusted for one of the cuts above referred to. The table 34 is in its raised position and the spacer 73 is open.

With the machine thus adjusted, the key blank is placed edgewise in the channel 54 fiatwise against the guide plate 57 and with the front end of the key blank against the stop block 64. While the key blank is thus held, the table 34 is depressed to bring the lower longitudinal edge of the key blank into contact with the cutter 27 to make the first cut. The engagement of the table 34 with the stop 48 limits the depth of this cut. The pressure on the table 34 is now released to permit it to return to normal position.

Next the key blank is turned side for side and placed in the channel 54 on the opposite side of the guide plate 57. Another operation similar to the first just described, is made to make the second cut, after the stop 49 is adjusted to make this out of the proper depth.

The side or longitudinal cuts are made by the cutter 2'8 while the key blank is held flatwise on the table 34, extend-ing edgewise in the passageway 72 and engaging the block 73 as a guide. At this time the block 73 is adjusted to trim the front end portion of the key blank as the same is fed endwise to the cutters 28. Next, the rear end portion of the key blank is trimmed by pressing the table to feed the key blank down onto the cutter 28 and then feeding the same endwise to the cutter 28 by a forward endwise movement. Next the block 53 is adjusted to make the cut on the other edge portion of the key blank. To make this cut, the key blank is turned end for end and fed to the cutter 28 in reverse order from which the other edge portion of the key blank was trimmed. It will be understood that the table 34 is always depressed to bring the key blank into contact with the cutter 28 each time a cut is made.

Finally, the spacer 73 is closed and the front end portion of the key blank is held with its front end against said spacer and the table 3 4 depressed to feed said key blank to the cutter 28 and thereby trim the front end thereof.

While there are herein disclosed but a limited number of embodiments of the structure, process and product of the invention herein presented, it is possible to produce still other embodiments without departing from the inventive concept herein disclosed, and it is desire-d, there fore, that only such limitations be imposed on the ap pended claims as are stated herein, or required by the prior art.

What I claim is:

1. In a machine of the class described, a base, a cutter journaled on the base, a table overlying the base and hinged thereto for raising and lowering movements, a supporting block resting on the table, a screw securing the block to the table, a channel in the block, a guide plate extending longitudinally through the channel perpendicular to the table :for directing work to the cutter, said guide plate having in its lower longitudinal edge portion a deep notch to provide a pair of legs, said guide plate at the notch straddling the block and resting thereon at the bottom of the channel, and with the legs extending through slots in the ends of the block and into a slot in the table.

2. 'In a machine of the class described, a main base, a bearing base detachably secured to the main base, a pair of laterally spaced bearings, a screw attaching each hearing to the bearing base to turn in a horizontal plane for axial alignment, an arbor journaled in the bearings, a cutter [fixed on the arbor, a thin plate extending between the bearings with its end portions fitted in slots in the bearings, and means for frictionally clamping the bearings onto the plate in axial alignment.

3. In a machine of the class described, a base, a pair of laterally spaced bearings mounted on the base, each to turn in a horizontal plane for axial alignment, a bushing fitted in each bearing and having therein a longitudinal slot extending through the ends thereof, an arbor journaled in the bushings, a cutter fixed on the arbor, a

thin plate extending between the bearings with its end portions fitted in slots in the bearings and with its inner longitudinal portion extending into the slots in the bushings, and means for frictionally clamping the bearings onto the plate in axial alignment.

4. In a machine of the class described, a base, a cutter journaled on the base, a table overlying the base and hinged thereto for raising and lowering movements, a pair of endw-ise spaced supporting blocks resting on the table, a screw securing each block to the table, a channel in the blocks, a guide plate extending longitudinally through the channel perpendicular to the table for directing work to the cutter, said guide plate having in its lower longitudinal edge portion .a deep notch to provide a pair of long legs, said guide plate at the notch straddling one of the blocks and resting thereon at the bottom of the channel, and with the legs extending through slots in the ends of said blocks and into a slot in the table, the other block having a pair of short legs extending into .the slot in the table.

5. In a machine of the class described, a main base, an arbor journaled on the base, a circular cutter lfixed on the arbor, means for driving the arbor, a work support overlying the arbor and having an upstanding guide plate provided with a deep notch in its lower longitudinal edge portion through which the cutter moves with a work- .ing clearance, 'a thin housing having an open back for the cutter, said housing having in its outer side a work passageway exposing the upper portion of the cutter and through which passageway the guide plate extends.

6. The structure defined in claim 5, turther including a motor base spaced below the main base and in which structure the means tor driving the cutter is an electric motor mounted on the motor base with its armature shaft in axial alignment with the arbor and directly attached thereto.

References Cited in the file of this patent UNITED STATES PATENTS 371,914 Arkin Oct. 25, 1887 735,099 Hormby Aug. 4, 1903 1,802,514 Johnson Apr. 23, 1931 2,544,175 Oslund Mar. 6, 1951 

